目的:检测质膜微囊结构蛋白caveolin-1和caveolin-2在低剂量内皮-单核细胞激活多肽-Ⅱ(EMAP-Ⅱ)开放血肿瘤屏障(BTB)过程中的磷酸化水平变化.方法:荷瘤Wistar大鼠被随机分成4组(每组12只):EMAP-Ⅱ0h、1h、2h和4h组.采用伊文思蓝渗透性实验评估各组BTB通透性变化情况;Westernblot和免疫荧光法检测大鼠脑胶质瘤组织毛细血管上磷酸化caveolin-1和caveolin-2的表达水平变化.结果:EMAP-Ⅱ作用1h时,BTB的通透性显著增强,随后逐渐降低,4h时恢复正常;EMAP-Ⅱ作用1h时,脑胶质瘤组织毛细血管上磷酸化caveolin-1和caveolin-2的表达水平均显著增高,随后逐渐降低,4h时恢复正常.结论:EMAP-Ⅱ可能通过caveolae介导的跨细胞途径来增强BTB的通透性,其机制与磷酸化caveo-lin-1和caveolin-2的表达水平上调有关.
Objective:To detect changes in the expression levels of phosphorylated caveolin (p- caveolin) -1 and - 2 in low - dose endothelial monocyte activating polypeptide - U ( EMAP - I1 ) - induced opening of blood - tumor barrier(BTB). Methods:Tumor - bearing rats were randomly divided into 4 groups( n = 12, each) : EMAP - II Oh, l h,2h and 4h groups. Evans blue method was used to evaluate the alterations in BTB permeability. Changes in the expression levels of p - caveolin - 1 and - 2 in rat brain capillaries were measured by Western blot and immuno- fluorescent assays. Results:The EB content in rat brain tumor tissues increased significantly at lh after EMAP- Ⅱ administration,and trended back toward the level of the EMAP - Ⅱ Oh group gradually by 4h. The expression levels of both p- caveolin- 1 and -2 in rat brain capillaries were significantly increased at l h, and decreased gradually to- ward the untreated level thereafter. Conclusion:EMAP - Ⅱ may induce opening of the BTB via caveolae - mediated transcellular pathway ,which is associated with the upregulation of p - caveolin - 1 and -2.